1. Field of the Invention
The present invention relates generally to an exhaust system for motor vehicles. More particularly, the invention relates to an exhaust system for motor vehicles such as two-wheeled and three-wheeled motor vehicles and the like having at least one rear wheel and a rear cowling member extending over the rear wheel so as to substantially cover same.
2. Description of Relevant Art
Within an exhaust pipe operably connected to a gasoline engine there are generally produced pulsating waves at positive and negative pressures induced by exhaust, which pulsating waves affect the exhaust action (a dynamic effect by the exhaust pipe) and further affect the output characteristic of the engine.
Therefore, characteristics of the exhaust system such as inside diameter, length, capacity and shape, which define the characteristic of such pulsating waves, are important factors affecting the engine performance.
Particularly, in motor vehicles such as two-wheeled and three-wheeled motor vehicles and the like, characteristics of the exhaust system are not only relatively important in relation to the weight and dimension of the entire vehicle body but also greatly affect the external appearance. Accordingly, it has been desired to provide an exhaust system having favorable dimensional characteristics, i.e., by arranging the system so that it is capable of decreasing the aforesaid pulsating waves to an appropriate extent while attaining a favorable and novel external appearance.
Moreover, the magnitude of air resistance during travel of motor vehicles such as two-wheeled and three-wheeled motor vehicles and the like depends on the projected area of the front portion of the vehicle, as well as other considerations such as the rider's driving posture and manner of dress. Therefore, it has been attempted in vehicle manufacture to decrease such projected area. Also, with respect to an exhaust pipe disposed on a side of a motor vehicle, which pipe is normally substantially circular in section, it has been desired to suppress the amount of projection thereof in the vehicular transverse direction by taking its shape into consideration while also taking its external appearance into consideration.
The present invention effectively overcomes the above-mentioned problems encountered in the exhaust system in motor vehicles such as two-wheeled and three-wheeled motor vehicles and the like.